Samsung Galaxy Apps IAP 3 error

Hi! Do any of you managed to integrate Samsung Galaxy App store IAP functionality to you Unity project? I followed the guide and managed to get "App purchase successful" popup, but after that the "Waiting..." popup stays there (animation still moving) and there is no way I can dismiss it. Another strange is my app changes to plane white screen, when interacting with the IAPHelper. I am using Unity 5.2.4 http://i.imgur.com/uH40rx9.png